In-situ spectral process monitoring

ABSTRACT

Increasing the precision of process monitoring may be improved if the sensors take the form of travelling probes riding along with the flowing materials in the manufacturing process rather than sample only when the process moves passed the sensors fixed location. The probe includes an outer housing hermetically sealed from the flowing materials, and a light source for transmitting light through a window in the housing onto the flowing materials. A spatially variable optical filter (SVF) captures light returning from the flowing materials, and separates the captured light into a spectrum of constituent wavelength signals for transmission to a detector array, which provides a power reading for each constituent wavelength signal.

BACKGROUND

Manufacturing processes used in the preparation of pharmaceuticals,food, distillates and chemical compounds may include some type of sensorinspection of the mixing process, for example, spectral, pH, and thermalinterrogation. These sensors are typically attached to a wall of aprocessing vessel, and monitor parameters of the process using a probeprotruding into the manufacturing process. However, the stationarynature of sensors having a fixed position limits inspection capabilitiesto the product in the immediate vicinity of the sensor's fixed positionand may not provide information about other parts of the process.

A collimating element may be required prior to variable optical filtersto prevent the spectral selectivity of the linearly variable filter frombeing degraded. Degradation may happen because the optical filter mayinclude a stack of thin dielectric films, and the wavelength-selectiveproperties of thin film filters are generally dependent on the angle ofincidence of incoming light, which may deteriorate spectral selectivityand wavelength accuracy of thin film filters. However, for the device inthe present disclosure it may be beneficial to reduce the size of thespectrometer even more by eliminating bulky lenses.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram of a top view of a probe;

FIG. 2 is a diagram of a cross-sectional view of the probe of FIG. 1;

FIGS. 3a to 3d are diagrams of alternative shapes for the probe of FIG.1;

FIG. 4 is a diagram of an isometric view of the probe of FIGS. 1 and 2;

FIG. 5 is a diagram of a side view of a dual SVF filter;

FIG. 6 is a diagram of a side view of a spectrometer;

FIGS. 7a and 7b is a diagram of side and end views, respectively, of aV-shaped mixing vessel for use with the probe of FIGS. 1 to 4;

FIG. 8 is a diagram of a settling tank for use with the probes of FIGS.1 to 4; and

FIG. 9 is a diagram of a process for use with the probes of FIGS. 1 to4.

DETAILED DESCRIPTION

Spectral evaluation at various times and locations in a flowingmaterial, such as liquids, powders and gas, provides powerful processmonitoring capabilities. FIG. 1 is a diagram of a top view, and FIG. 2is a diagram of a cross-sectional view of a probe 1 according to anexample implementation described below. The probe 1 may be a spatiallyvariable filter (SVF) based spectral probe and includes an outer housing2, which may be monolithic or multi-sectional in form and may behermetically sealed, thereby making the probe 1 robust for applicationsin which it is immersed in a material the probe is to measure. The outerhousing 2 may take one of several shapes or combinations thereofincluding, but not limited to, spherical 1 (FIGS. 1 and 2), toroidal 1A(FIG. 3A), rounded toroidal 1B (FIG. 3B), ellipsoid or prolate spheroid(football) 1C (FIG. 3C), and cylindrical 1D (FIG. 3D) depending on theapplication. In one example implementation, the outer housing 2 may bemade of or include a corrosion-resistant material, such as stainlesssteel or a polymer material.

The outer housing 2 may include one or more windows 4 spaced apart onthe outer housing 2 or the outer housing 2 may be entirely transparent,i.e. a continuous window. In various example implementations, the outerhousing 2 may include any of 1 to 20 or more windows 4. The one or morewindows 4 enable light reflected or refracted from the surroundingmaterial to be captured by a corresponding linearly or spatiallyvariable optical filter (SVF) 7 inside the probe 1. The reflected orrefracted light may originate from one or more internal light sources 6,an external light source (not shown), ambient light, or a combinationthereof. The SVF 7 may be discrete or continuously varying. The filter 7may be based on other dispersive elements, e.g. gratings, or prisms, ormay be based on other technology, such as MEMS, dyes and pigments, FTIR,and Raman. The SVF 7 separates the captured light into a spectrum ofconstituent wavelength signals for analysis.

The windows 4 may be made of any suitable material, which is opticallytransparent for the desired transmission and reflected or refractedwavelengths, e.g., sapphire, silicon, Teflon, glass, etc. The internallight source 6 may be any suitable light source, e.g., a tungsten or LEDlight source, for transmitting the required wavelength band of light,e.g., visible (350 nm to 900 nm) and/or near infrared (NIR). In anexample implementation, for near infrared, the light source 6 may becomprised of one or more onboard incandescent lamps, e.g. vacuumtungsten lamps, that provide broadband illumination, e.g., over 500 nm,over 700 nm, or over 1000 nm across the active range of the instrument,e.g., for the NIR in the 900 nm to 1700 nm range or in the 900 nm to2150 nm range. One lamp 6 is sufficient; however, two lamps providesmore light for the sample to interact with, hence shorter integrationtimes.

In an example implementation, as illustrated in FIG. 2, a conduit 19extending from an opening in the outer housing 2 into the outer housing2 to an outlet in the outer housing 2 may be provided enabling thepassing of the flowing material, e.g. liquid, in between the lightsource 6 and the SVF 7 within the outer housing 2 for generating atransmission spectrum via the photodetectors 8 and the controller 12.The entire conduit 19 may be transparent to the transmitted lightproviding the necessary window for light to be transmitted from thelight source 6 to the SVF 7, or one or more sections of the conduit 19may be transparent providing the required window(s) for transmitted.refracted or reflected light.

Mounted beneath each SVF 7 is an array of photodetectors 8 forming aspectrometer 15 and generating a power reading for each constituentwavelength signal, thereby providing a spectrum of the reflected light.Each of the spectrometers 15 in each probe 1 may have a same spectralrange or different spectrometers 15 may have different spectral ranges,e.g., overlapping or adjacent, to enable a broad spectral range to bestitched together from the individual spectrometers 15. Another exampleimplementation may include a plurality of fiber bundles, each connectingto a single spectrometer 15 for light supply and data collection. Eachbundle may communicate with a different window 4, and may besequentially coupled to the single spectrometer 15.

The photodetectors 8 may be a broadband detector array, e.g. more than500 nm, more than 600 nm, or more than 700 nm wide, such as an indiumgallium arsenide (InGaAs) detector covering 950 nm to 1650 nm, which maybe extended to 1150 nm to 2150 nm, if desired or required. For multiplespectrometer probes 1 and multiple probe systems, differentspectrometers 15 within each probe 1 and different probes 1 within eachsystem may have light sources 6, filters 7 and photodetectors 8 withdifferent spectral ranges to cover a wider spectrum, e.g. ultraviolet toinfrared, to enable a broad range of tests.

An inner frame 11 may be mounted inside the outer housing 2 forsupporting all of the SVF's 7 and photodetector arrays 8. The innerframe 11 may be made of or include one or more of a printed circuitboard material, plastic, metal, ceramic, or other suitable material. Acontroller 12 may be mounted within or on the inner frame 11. Thecontroller 12 may comprise suitable hardware, e.g., processor and memorychips mounted on printed circuit boards 13, along with suitable softwarefor controlling all of the probes features, including spectrumgeneration, storing, and analysis, thereby providing a self-containedspectral probe 1 for immersion in the material, in particular when thematerial is moving or flowing in production.

Other types of sensors 14 that may be included within the probe 1include, but are not limited to, pH sensors, temperature sensors,pressure sensors, voltage sensors, velocity sensors, accelerometers,gyroscopes, and onboard cameras and forward looking infrared (FUR)sensors. In various example implementations, the probe 1 may includemultiple similar and/or different sensors positioned around the outerhousing 2 of the probe 1. These multiple sensors 14 can enable multipledata sets to be interrogated and improve the quality of the variousmeasurements. Each of the sensors 14 along with the photodetector arrays8 are connected to the controller 12 for control and data storage.

Each probe 1 may include one or more shutters 16 within the outerhousing 2, presenting calibration standards that moves into and out oflocation in front of each spectrometer 15 as part of a calibrationprocess. In the example implementation illustrated in FIG. 2, theshutter 16 is mounted on the end of a rotating arm 17, which rotatesabout a central anchor 18 connected to the inner frame 11. The shutter16 may recalibrate each spectrometer 15 after a predetermined time,e.g., at least every 5 minutes of operation, or after a predeterminednumber of uses, e.g., at least after every 300 spectral readings.

The shutter 16 includes a calibrated reflectance standard to be rotatedbetween the light source 6 and the window 4 to reflect the light fromeach light source 6 directly to the corresponding SVF 7. The reflectancefrom this known standard is then compared to previous tests to determineany change in illumination inside the probe 1.

A communication module 21 is provided to enable control and/or datasignals to be sent between the controller 12 and a base station (shownin FIGS. 7 to 9). In an example implementation, the base station may bemonitored by process monitoring engineers. In another exampleimplementation, the base station may include an automated processcontrol system. The communication module 21 may be one or more of awireless transceiver, a tethered communication cable connection, a phototransceiver, or an acoustical transceiver. A communication module 21that is wireless may require antennas (not shown) positioned within oroutside the outer housing 2 to achieve a real-time data transferconnection with the base station.

The probe 1 may be self-powered with the use of replaceable ofrechargeable batteries 22 and/or may be powered by a tethered powercable 24 adjacent to or coordinated with the optional communicationcable connection (not shown). The power cable 24 may act as acommunication line interconnecting the communication module 21 with thebase station, and a tether for retrieving the probe 1 from the flowingmedia. Since the outer housing 2 may be hermetic, in an exampleimplementation, the batteries 22 may be recharged using an inductionconnection. In an example implementation, the controller circuit 12 mayemploy the use of a position system tracker (not shown), e.g., a globalpositioning system (GPS), to track the location of the probe 1 withinthe manufacturing or monitoring process. Another possible positiontracking system comprises a radio transmitter (not shown) in the probe 1for signaling an array of fixed directional radio receivers (not shown)positioned around a processing vessel. The array of fixed directionradio receivers may be used to coordinate the position of the probe 1within the fixed processing vessel or system, whereby the base stationand/or each probe's controller 12 may determine the probe's position. Aninertial measurement unit (IMU) (not shown) may also be provided toenable the controller 12 or the base station to monitor the probe 1 fororientation and direction of travel within the process vessel.

In one example implementation, the probe 1 may be compatible with theprocess it is intended to interrogate, for example, the outer housing 2may be made of IP67 or higher plastic NEMA 4, or the like, for packagehermiticity and dust ingress and compatible chemical resistance from thematerial it is immersed in. In an example implementation, the probe 1may have variable buoyancy to adjust its buoyancy for use in a liquidprocess. As stated earlier, the probe 1 may be free to move within theprocess or may be attached to a fixed object via tether for post processretrieval.

In an example implementation, the outer housing 2 may be ruggedized tohandle impacts from mixing or pressurized actions within the manufactureprocess. In an example implementation, the probe 1 may be used in aprocess that requires extended monitoring times and the controller 12may include programming to instruct the photodetector arrays 8 andsensors 14 to change into low power “Stand by” modes to conserve powerduring long process cycles.

FIG. 4 is a diagram of an isometric view of a probe 1 according to anexample implantation described below. The outer housing 2 of the probe 1may include structural features that facilitate movement and stabilitywith and through the material in which the probe is immersed. Thestructural features may include, for example, dimples, small or largeribs, stubs, semi-circular or rectangular ribs, veins, or fingers. Theexample implementation probe 1 in FIG. 4 includes a number of ribs 3.The structural features may provide protection for the probe 1 fromcontact with other objects, e.g., vessel walls. The structural featuresmay also provide enhanced mixing and/or reduced clumping within theflowing material as the probe 1 travels through the flowing material.The structural features may also help in maintaining orientation of theprobe 1 relative to the direction of the flow of the material in whichthe probe 1 is immersed, facilitate heat exchange with the material, anddirect the material to be measured in front of the sensor windows 4 formeasurement and for removing debris that may have become adheredthereto.

The outer housing 2 may also include a hatch 9 for accessing a storagecompartment 10. The hatch 9 may be opened by the controller 12 inresponse to a signal from the base station or in response to an internalsignal from the controller 12, e.g., a spectrum reading or other testsignal reaching a predetermined or desired level. In an exampleimplementation, the storage compartment 10 may contain a substance usedto facilitate a chemical process, e.g., a catalyst. In an exampleimplementation, the storage compartment 10 may contain a substance usedto mark a specific location, e.g., a dye. In an example implementation,the storage compartment 10 may contain a substance used to alter thechemical parameters of the substance in which the probe 1 is immersed,e.g., pH or toxicity. Alternatively, the hatch 9 may be opened inresponse to a signal from the controller 12 and/or the base station tocapture fluid from the material in which the probe is immersed in thestorage compartment 10 for further testing or for controlling buoyancyof the probe 1.

The probe 1 may also include a separate buoyancy system 31, which willenable the buoyancy of each probe 1 to be individually adjusted beforeinsertion into the flowing material or during active monitoring in theflowing material to enable the probe 1 to be guided or propelled to adifferent location, and different depths within the flowing material.The buoyancy system 31 may comprise a fluid expelling device forexpelling fluid from a storage tank or bladder 32, thereby decreasingthe density of the probe 1 and/or a fluid intake device for capturingsurrounding fluid, thereby increasing the density of the probe 1.

The probe 1 may also include a propulsion system 33, which will enablethe position of each probe 1 to be adjusted by the controller 12 and/orthe base station. The propulsion system 33 may include the release of apressurized burst of fluid stored in a storage tank, an electro-magnet,which may be energized to attract the probe 1 towards a metallicstructure in the processing tank, or a propeller.

In certain applications, a window cleaner system 25, which may becontrolled by the controller 12, may be provided to periodically wipe orremove accumulated material off of the exterior of the windows 4. Thecleaner system 25 may comprise an external concentric shell (not shown)with a wiper system mounted on the outer housing 1. The wiper system mayinclude a wiper 26 mounted on an a rotating or translating arm 27 whichmay be swept across the windows 4. Alternatively or in addition to thewiper system, the propulsion system 33 may spin the probe 1 at highspeed within the volume of flowing material to throw off any accumulatedmaterial on the windows 4 by centrifugal force. Other cleaning systemsmay include one or more of a sonic agitator to provide sonic agitationto clear the windows 4, a heater to heat the windows 4 and to drive offmoist powders, and a source of electricity to generate an electricdischarge.

FIG. 5 is a diagram of a side view of a dual SVF filter according to anexample implementation described below. FIG. 6 is a diagram of a sideview of a spectrometer according to an example implementation describedbelow. The spatially variable filter (SVF) 7 comprises a centerwavelength of a passband varying, e.g. linearly or non-linearly, alongan x-axis, and in some embodiments in the y-axis forming a 2D spatiallyvariable filter (SVF).

Accordingly, the SVF 7 may include sequentially disposed upstream 35Aand downstream 35B spatially variable bandpass optical filters (SVF)separated by a predetermined fixed distance L in an optical path 36 ofan optical beam 37, as disclosed in U.S. patent applications Ser. Nos.14/608,356 and 14/818,986, entitled “OPTICAL FILTER AND SPECTROMETER” bySmith et al, filed Aug. 5, 2015, which are herein incorporated byreference. The upstream SVF 35A and the downstream SVF 35B each have abandpass center wavelength λ_(T) varying in a mutually coordinatedfashion along a common first direction 38 represented by the x-axes. Thefirst direction 38 is transversal to the optical path 36. By way of anon-limiting example, the bandpass center wavelength λ_(T) of both theupstream 35A and downstream 35B SVF have respective monotonic, lineardependences. The configuration of the optical filter 7 enables adependence of spectral selectivity of the optical filter 7 on a degreeof collimation of the optical beam 37 to be lessened as compared to acorresponding dependence of spectral selectivity of the downstream SVF35B on the degree of collimation of the optical beam 37.

In the example of FIG. 5, the upstream 35A and downstream 35B SVF arealigned with each other, so that the reference point x₀ corresponding tothe reference bandpass center wavelength λ₀ of the downstream filter 35Bis disposed directly under the reference point x₀ corresponding to thereference bandpass center wavelength λ₀ of the upstream filter 35A. Theupstream filter 35A functions as a spatial filter for the downstreamfilter 35B, defining a predetermined or preset angle of acceptance 39for the downstream filter 35B. The angle of acceptance 39 is limited byleft 40L and right 40R marginal rays at the reference wavelength λ₀,each propagating at the angle θ to a normal 36 to the upstream 35A anddownstream 35B filters and striking downstream filter 359 at the samereference point x₀. The angle of acceptance 30 may be derived from apassband 41A of the upstream filter 35A as follows.

In the geometry illustrated in FIG. 5, the left marginal ray 40L strikesthe upstream filter 35A at a location x₀-Δx. Transmission wavelengthλ_(L), at that location is, according to Eq. (1), λ_(L)=λ₀−DΔx. Sincethe left marginal ray 40L is at the reference wavelength λ₀, the leftmarginal ray 40L will be attenuated depending on a selected andpredetermined bandwidth of the passband 41A of the upstream SVF 35A; forsake of this example, e.g. a 10 dB bandwidth is taken to be 2DΔx. Thus,the left marginal ray 40L will be attenuated by the predeterminedattenuation, e.g. 10 dB. Similarly, the right marginal ray 40R strikesthe upstream SVF 35A at a location λ₀+Δx. Transmission wavelength λ_(R)at that location is, according to Eq. (1), λ_(R)=λ₀+DΔx. The rightmarginal ray 40R will also be attenuated by the predeterminedattenuation, e.g. 10 dB. All rays at the reference wavelength λ₀ withinthe acceptance angle 39 will be attenuated by a value smaller than thepredetermined level, e.g. 10 dB; and all rays at the referencewavelength λ₀ outside the acceptance angle 39 will be attenuated by avalue larger than the predetermined level, e.g. 10 dB, thereby greatlyreducing the amount of light, at incident angles greater than theacceptance angel 39, from being transmitted to the downstream SVF 35B,thereby eliminated the need for bulky collimating lenses and optics. Theupstream SVF 35A functions as spatial filter, effectively limiting thenumerical aperture (NA) of incoming light to be separated in individualwavelengths by the downstream SVF 35B. This results in reduction of thedependence of spectral selectivity of the SVF 7 in comparison with thecorresponding dependence of the spectral selectivity of the singledownstream SVF 35B on the degree of collimation of the optical beam 37.The term “spectral selectivity” may include such parameters as passbandwidth, stray light rejection, extinction ratio, etc.

The center wavelengths λ_(T) of the upstream 35A and downstream 35B SVFmay be monotonically increasing or decreasing in the first direction 38.The dependence of the bandpass center wavelength λ_(T) on thex-coordinate along the first direction 38 of the upstream SVF 35A anddownstream 35B SVF may be identical, or different to enable adjustmentof the acceptance angle and/or wavelength response of the optical filter7. In one embodiment, the bandpass center wavelengths λ_(T) of theupstream SVF 35A and downstream SVF 35B are aligned with each other,such that a line connecting positions corresponding to a same bandpasscenter wavelength λ_(T) of the upstream SVF 35A and the downstream SVF35B forms an angle of less than a predetermined amount, e.g., 30°, withthe normal 36 to the downstream SVF 35B. For non-zero angles with thenormal 36, the acceptance cone 39 may appear tilted. Thus, it ispossible to vary the acceptance cone 39 direction by offsetting theupstream SVF 35A and the downstream SVF 35B relative to each other inthe first direction 38. For a better overall throughput, a lateraldistance Δx₁ along the first direction 38, corresponding to a bandwidthof the upstream SVF 35A, may be larger than a corresponding lateraldistance Δx₂ along the first direction 38, corresponding to a bandwidthof the downstream SVF 35B. In one example implementation, the upstreamSVF 35A and the downstream 35B SVF each have a 3 dB passband no greaterthan 10% of a corresponding wavelength range of the upstream SVF 35A andthe downstream SVF 35B.

Referring to FIG. 6, the spectrometer 15 includes the optical filter 7and a photodetector array 8 disposed in the optical path downstream ofthe downstream SVF 35B. The photodetector array 8 may include pixels 44disposed along the first direction 38 and optionally along a secondperpendicular direction (into the page) for detecting optical powerlevels of individual spectral components of the optical beam, e.g.,reflected by the flowing material from the light source 6. In an exampleimplementation, the photodetector array may be the 2D photodetectorarray disclosed in U.S. patent application Ser. No. 14/818,986, entitled“OPTICAL FILTER AND SPECTROMETER” by Smith et al, filed Aug. 5, 2015,which is incorporated herein by reference. Accordingly, the optical beammay be converging, diverging, collimated, etc. As explained above, thedual-filter structure of the optical filter 7, including the upstreamSVF 35A and the downstream SVF 35B results in lessening the dependenceof spectral selectivity of the optical filter 7 on a degree ofcollimation of the returning light.

In one example implementation, the photodetector array 8 may be indirect contact with the downstream SVF 35B. The photodetector array 8may be flooded with a potting material so as to form an encapsulation45. One function of the encapsulation 45 is to insulate thephotodetector array 8, while not obscuring a clear aperture 46 of thedownstream SVF 35B of the optical filter 7. Another function of theencapsulation 45 is to protect edges of the upstream 35A and downstream35B filters from impact, moisture, etc.

Applications

FIGS. 7a and 7b are diagrams of side and end views, respectively, of aV-shaped mixing vessel for use with the probes 1. With reference toFIGS. 7a and 7b , a plurality of the probes 1 may be used in amonitoring system for a batch processing system, e.g., in thepharmaceutical industry. A processing tank 51 includes a support frame52 for supporting a mixing vessel, such as V-shaped mixing vessel 53.The mixing vessel 53 includes at least one input port 54 for inputtingthe raw ingredients, and at least one output port 55 for discharging thefinished product. An agitator or chopper 56 may be provided inside themixing vessel 53 to reduce the size of the raw ingredients and/or mixthe various raw ingredients together. The agitator 56 may be rotatedusing a sprocket and chain structure 57, or some other suitable drivingassembly, which is driven by a motor 58. A control system 59 may beprovided for controlling the input of the ingredients, the activationand speed of the agitator 56, as well as the timing of the discharge ofthe finished product via output port 55. The control system 59 may becontrolled automatically according to pre-set programming stored onnon-transitory memory actuated by a computer controller or may requirehuman intervention at selected times.

One or more probes 1 may be placed in with the raw ingredients, or evenseparately with different raw ingredients that are input throughseparate input ports 54, and follow along with the raw ingredients asthey mix with each other and/or react with each other due to theirchemical properties or other external factors, such as a change intemperature or pressure, or the addition of a catalyst. Throughout theprocess, the probes 1, via the controller 12 and the communicationmodule 21 may continually transmit spectrum data to the control system59 (base station), e.g., wirelessly via WIFI, at predetermined timeintervals to provide constant status updates of the chemical process.The control system 59 and/or the controller 12 may utilize the spectrumdata and any other test data collected by the other sensors 14 in one ofmany different ways. In one example implementation, the control system59 and/or the controller 12 may utilize the spectrum and test data todetermine when the process is complete, i.e. to shut the process off,and output the finished product. In addition, the control system 59and/or the controller 12 may utilize the spectrum and test data toadjust the frequency or speed of the agitator 56 and/or to adjust theparameters of the chemical process, e.g. adjust any one or more of thetemperature, the pressure, and the amount of catalyst. For multi-stepprocesses, the control system 59 and/or the controller 12 may utilizethe spectrum and test data to initiate subsequent steps in the process,e.g. as the spectrum and test data reach desired output levels. Thecontrol system 59 and/or the controller 12 may even distributeadditional catalysts or ingredients at specific times based on thespectrum and test data from the storage compartment 10 via hatch 9.

The control system 59 and/or the controller 12 may identify the positionof the various probes 1 using each probe's positioning system, e.g.,GPS, and may prioritize which probe 1 has greater significance indetermining a next step based on the position of that probe 1. Inaddition, since each probe 1 may have a plurality of spectrometers 15,the control system 59 and/or the controller 12 may average the spectrumdata for each probe 1. The averaging process may include eliminatinghigh and low measurements or any measurement outside a predetermineddeviation from the average of the remaining measurements. Averaging mayinclude averaging the different spectra from the different windows4/spectrometers 15 within each probe 1, and/or average the spectra frommultiple probes 1 at multiple locations throughout the volume of flowingmaterial. The controller 12 or the control system 59 may also includesuitable programming to perform other spectrum processing includingdifferencing similar or different spectra regions to compare readings orcombining different overlapping or adjacent sprectra to generate a widerspectrum.

The position of each probe 1 may be adjusted by utilizing the onboardpropulsion system 33, the onboard buoyancy system 31, or by using aprocess propulsion system external to each probe 1, such as anelectro-magnet 60 energized at a predetermined or desired location toattract one or more of the probes 1 in a required direction or into adesired zone of the vessel 53. In this system, the probes 1 can easilybe collected for re-use when the finished product is output the outletport 55.

With reference to FIG. 8, the probes 1 may be used in a continuousprocess including a settling tank 61. The settling tank 61 includes aninput port 62 for inputting raw or unprocessed ingredients proximate themiddle of the tank 61, and an agitator or rake 63, which is mounted onthe end of rotating shaft 64, and rotates around the bottom of thesettling tank 61. An output port 65 is provided in the bottom of thesettling tank 61 for outputting processed material, e.g. thickenedliquid. An overflow channel 66 is provided around the top of thesettling tank 61 to capture all the lighter fluid and materials, whichrise to the top of the settling tank 61.

One or more probes 1 may be placed in with the raw ingredients throughinput port 62, and follow along with the raw ingredients as they mixwith each other and/or react with each other due to their chemicalproperties or other external factors, such as a change in temperature orpressure, or the addition of a catalyst. Throughout the process, thecontrollers 12 may continually transmit spectrum data, e.g., wirelesslyvia WIFI, to a base station 69 at predetermined time intervals toprovide constant status updates of the chemical process. The basestation 69 and/or the controllers 12 may utilize the spectrum data andany other test data collected by the other sensors 14 in one of manydifferent ways. For example, the base station 69 and/or the controllers12 may simply utilize the spectrum and test data to determine when theprocess has reached a certain stage, i.e., outputs the finished productvia the output port 65. In addition, the base station 69 and/or thecontrollers 12 may utilize the spectrum and test data to adjust thefrequency or speed of the rake 64 and/or to adjust the parameters of thechemical process, e.g. adjust any one or more of the temperature, thepressure, and the amount of catalyst. For multi-step processes, the basestation 69 and/or the controllers 12 may utilize the spectrum and testdata to initiate subsequent steps in the process, e.g., as the spectrumand test data reach desired output levels. The controllers 12 and/or thebase station 69 may even distribute additional catalyst or ingredientsat specific times based on the spectrum and test data from the storagecompartment 10 via hatch 9.

The base station 69 and/or the controllers 12 may identify the positionof the various probes 1 using each probes positioning system, e.g., GPS,and may prioritize which probe 1 has greater significance in determininga next step based on the position. In addition, since each probe 1 mayhave a plurality of spectrometers 15, the base station 69 and/or thecontrollers 12 may average the spectrum data for each probe 1. Theaveraging process may include eliminating high and low measurements orany measurement outside a predetermined deviation from the average ofthe remaining measurements.

The position of each probe 1 may be adjusted by the controllers 12and/or the base station 69 utilizing the onboard propulsion system 33,the onboard buoyancy system 31 or by using a process propulsion systemexternal to each probe 1, such as an electro-magnet 68 energized at apredetermined or desired location to attract one or more of the probes 1in a required direction or into a desired zone of the settling tank 61.In this system, the probes 1 may have different buoyancy properties,e.g. one for settling to the bottom for output the output port 65 andone for rising to the top for output the overflow channel 66.Accordingly, the probes 1 can easily be collected for re-use when thefinished product is output the various ports 65 and 66.

With reference to FIG. 9, a multi-step process, such as a brewingprocess, may include several steps, e.g. lautering, boiling, fermenting,conditioning, filtering, and packaging, which may require precisionmonitoring provided by a monitoring system including a base station 70and a plurality of probes 1 communicating via a wireless network, e.g.,WIFI. The probes 1 may be inserted into each processing tank at eachstep or the probes 1 may travel with the ingredients through varioussteps and processing vessels.

Malting is the process where barley grain 71 is made ready for brewing.When malting is complete, the grains 71 are milled or crushed in a mill72 to break apart the kernels and expose the cotyledon, which containsthe majority of the carbohydrates and sugars.

Mashing converts the starches released during the malting stage intosugars that can be fermented. The milled grain is mixed with hot waterin a large vessel known as a mash tun 73. In this vessel, the grain andwater are mixed together to create a cereal mash. During the mash,naturally occurring enzymes present in the malt convert the starches(long chain carbohydrates) in the grain into smaller molecules or simplesugars (mono-, di-, and tri-saccharides). This “conversion” is calledsaccharification. The result of the mashing process is a sugar richliquid or “wort”, which is then strained through the bottom of the mashtun 73 or in a separate tank 74 in a process known as lautering. Theprobes 1 may be deposited into the mash tun 73 to monitor theconcentration of enzymes and the concentration of starches in the wort.Prior to lautering, the mash temperature may be raised to about 75-78°C. (167-172° F.) (known as a mashout) to deactivate enzymes. Probes 1may be used near the bottom of the mash tun 73 or lautering tank 74 toensure the temperature is within the desired range throughout thecontainer using a temperature sensor 14, and to ensure the concentrationof enzymes is reduced to a desired or acceptable level using one of theprobe spectrometers. Additional water may be sprinkled on the grains toextract additional sugars in a process known as sparging.

The wort is moved into a large tank 75 known as a “copper” or kettlewhere it is boiled with hops and sometimes other ingredients 76, such asherbs or sugars. This stage is where many chemical and technicalreactions take place, and where important decisions about the flavor,color, and aroma of the beer are made. The boiling process serves toterminate enzymatic processes, precipitate proteins, isomerize hopresins, and concentrate and sterilize the wort. Hops add flavor, aromaand bitterness to the beer. The spectrum signals from the probes 1 maybe used to determine the concentrations of the various elements and thecolor of the wort At the end of the boil, the hopped wort settles toclarify in a vessel called a “whirlpool” 77, where the more solidparticles in the wort are separated out.

After the whirlpool 77, the wort is rapidly cooled via a heat exchanger78 to a temperature where yeast can be added. The heat exchanger 78 iscomprised of tubing inside a tub of cold water. It is very important toquickly cool the wort to a level where yeast can be added safely asyeast is unable to grow in high temperatures. Accordingly, temperaturesensors 14 on the probes 1 may quickly determine when the wort hascooled to the required temperature evenly throughout the heat exchanger78. After the wort goes through the heat exchanger 78, the cooled wortgoes into a fermentation tank 79. A type of yeast is selected and added,or “pitched”, to the fermentation tank 79. When the yeast is added tothe wort, the fermenting process begins, where the sugars turn intoalcohol, carbon dioxide and other components. In the fermentation tank79, the probes 1 provide spectral signals relating to the concentrationof those elements. When the fermentation is complete the brewer may rackthe beer into a new tank, called a conditioning tank 80. Conditioning ofthe beer is the process in which the beer ages, the flavor becomessmoother, and flavors that are unwanted dissipate. Here the spectrumsignals from the probes 1 provide a clear indication of when the beerhas reached its optimum condition, as well as the monitoring of othercharacteristics, such as pH. After conditioning for a week to severalmonths, the beer may be filtered using a filter 81 and force carbonatedfor bottling, or fined in the cask.

The probes 1 may also be used in a much larger monitoring system, suchas in active rivers, lakes, oceans and other waterways to monitor theconcentration of various elements, such as pollutants, e.g. oil spills,along with other contributing factors, for example temperature and pH.The combination of the location and time of detection, and the type(s)of the pollutant detected, may enable determination of the source ofpollution, as well as the resultant damage, e.g. changes in watercharacteristics, downstream.

As the size of the probes 1 decrease, they may also be used formonitoring humans or other animals in-vivo. In particular, a probe 1 maybe ingested and the spectral data may be transmitted to a doctor's basestation as the probe 1 traverses the patient's digestive system tomonitor content, pH, temperature and various other characteristics.

In an example implementation, the probes 1 may be dropped from some formof flying machine, e.g., airplane, balloon, helicopter or spacecraft, tomonitor various atmospheric characteristics, e.g., ozone, allergens,pollutants.

The present disclosure is not to be limited in scope by the specificexample implementations described herein. Indeed, other implementationsand modifications, in addition to those described herein, will beapparent to those of ordinary skill in the art from the foregoingdescription and accompanying drawings. Thus, such other implementationand modifications are intended to fall within the scope of the presentdisclosure. Further, although the present disclosure has been describedherein in the context of a particular implementation in a particularenvironment for a particular purpose, those of ordinary skill in the artwill recognize that its usefulness is not limited thereto and that thepresent disclosure may be beneficially implemented in any number ofenvironments for any number of purposes. Accordingly, the claims setforth below should be construed in view of the full breadth and spiritof the present disclosure as described herein.

We claim:
 1. A probe, comprising: a hermetically sealed outer housing; alight source for transmitting light onto a material; a window in theouter housing, wherein the window is optically transparent at one ormore of transmitted, refracted or reflected wavelengths of light fromthe material; an optical filter for capturing light transmitted,refracted or reflected from the material, and for separating thecaptured light into a spectrum of constituent wavelength signals; and adetector array for providing a power reading for a plurality of theconstituent wavelength signals.
 2. The probe according to claim 1,wherein the optical filter comprises a spatially variable optical filtercomprising: an upstream spatially variable bandpass optical filter; anda downstream spatially variable bandpass optical filter sequentiallydisposed downstream of the upstream variable bandpass optical filter andseparated from the upstream spatially variable bandpass optical filterby a fixed predetermined distance along an optical path of the capturedlight, wherein the upstream and downstream spatially variable bandpassoptical filters each have a bandpass center wavelength that varies in amutually coordinated fashion along at least a common first directiontransversal to the optical path, and wherein light at each bandpasscenter wavelength along the upstream spatially variable optical filteroutside a predetermined acceptance angle is attenuated by more thanlight inside the predetermined acceptance angle.
 3. The probe accordingto claim 1, wherein the outer housing comprises a shape selected fromthe group consisting of spherical, cylindrical, prolate spheroid,ellipsoid, and toroidal.
 4. The probe according to claim 1, wherein theouter housing comprises structural features arranged on the outside ofthe outer housing.
 5. The probe according to claim 4, wherein thestructural features include one or more of dimples, stubs, semi-circularor rectangular ribs, veins, or fingers.
 6. The probe according to claim1, further comprising: a controller for storing the power readings foreach constituent wavelength signal; and a communication device fortransmitting the power readings to a remote base station.
 7. The probeaccording to claim 6, wherein the communication device is a wirelesscommunication device.
 8. The probe according to claim 1, furthercomprising a positioning system tracker for determining an exactposition or orientation of the probe.
 9. The probe according to claim 1,further comprising a propulsion system for propelling the probe whenimmersed in the material.
 10. The probe according to claim 1, furthercomprising a buoyancy adjusting system for adjusting the buoyancy of theprobe when immersed in the material.
 11. The probe according to claim 1,further comprising a storage compartment, and a hatch on the outerhousing, the hatch operable to open and close the storage compartment.12. The probe according to claim 11, further comprising a controller forstoring the power readings for each constituent wavelength signal;wherein the controller comprises programming for signaling the hatch toopen and release a substance from the storage component when the powerreadings reach a predetermined level.
 13. The probe according to claim6, wherein the communication device is a wired communication device; andwherein the outer housing is tethered to a structure.
 14. The probeaccording to claim 1, further comprising a window cleaner for removingdebris from the window.
 15. The probe according to claim 1, wherein thelight source is mounted inside the outer housing for transmitting lightthrough the window onto the material.
 16. The probe according to claim1, wherein the outer housing comprises a conduit extending therethroughfrom an opening in the outer housing to an outlet in the outer housingin between the light source and the optical filter.
 17. The probeaccording to claim 1, further comprising: a plurality of windows spacedapart around the outer housing; a plurality of light sources inside theouter housing for transmitting light through a corresponding one of thewindows onto the material; a plurality of optical filters for capturinglight transmitted through, and reflected or refracted from the material,and for separating the captured light into a spectrum of constituentwavelength signals; and a plurality of detector arrays for providing apower reading for a plurality of the constituent wavelength signals. 18.The probe according to claim 17, further comprising a controller forstoring the power readings for each constituent wavelength signal;wherein the controller includes programming for averaging the powerreadings from the constituent wavelength signals.
 19. The probeaccording to claim 17, further comprising a controller for storing thepower readings for each constituent wavelength signal; wherein theoptical filters include different spectral passbands; and wherein thecontroller includes programming for combining the power readings from atleast two detector arrays with different spectral passbands forgenerating a combined spectrum.
 20. The probe according to claim 17,further comprising a shutter moveable within the outer housing intoposition between each light source and the corresponding optical filterfor recalibrating each photodetector array after a predetermined timeperiod.
 21. A monitoring system for monitoring a flowing materialcomprising: a plurality of probes, each probe comprising: a hermeticallysealed outer housing; a light source for transmitting light onto amaterial; a window in the outer housing, wherein the window is opticallytransparent at one or more of transmitted, refracted or reflectedwavelengths of light from the material; an optical filter for capturinglight transmitted, refracted or reflected from the material, and forseparating the captured light into a spectrum of constituent wavelengthsignals; and a detector array for providing a power reading for aplurality of the constituent wavelength signals; and a base station incommunication with said plurality of probes.
 22. The monitoring systemaccording to claim 21, wherein said base station receives power readingsfrom said plurality of probes, and adjusts parameters for the flowingmaterial in response to the received power readings.
 23. A method ofmonitoring a flowing material comprising: placing at least one probeinto the flowing material; each probe comprising: a hermetically sealedouter housing; a light source for transmitting light onto a material; awindow in the outer housing, wherein the window is optically transparentat one or more of transmitted, refracted or reflected wavelengths oflight from the material; an optical filter for capturing lighttransmitted, refracted or reflected from the material, and forseparating the captured light into a spectrum of constituent wavelengthsignals; and a detector array for providing a power reading for aplurality of the constituent wavelength signals and repeatedly receivingpower readings at a base station from each of said probes at differentlocations as the probes travel along with the flowing material.
 24. Themethod according to claim 23, further comprising: adjusting parametersof said flowing materials in response to said power readings.
 25. Themethod according to claim 23, further comprising: adjusting the positionof one of the probes by activating a propulsion system.
 26. The methodaccording to claim 23, further comprising releasing a substance fromwithin at least one of said probes.
 27. The method according to claim23, further comprising capturing a sample of the material.